Can we measure the collapse time of a post-merger remnant for a future GW170817-like event?

Abstract

Measuring the collapse time of a binary neutron star merger remnant can inform the physics of extreme matter and improve modelling of short gamma-ray bursts and associated kilonova. The lifetime of the post-merger remnant directly impacts the mechanisms available for the jet launch of short gamma-ray bursts. We develop and test a method to measure the collapse time of post-merger remnants. We show that for a GW170817-like event at $\sim 40$Mpc, a network of Einstein Telescope with Cosmic Explorer is required to detect collapse times of $\sim 10$ms. For a two-detector network at A+ design sensitivity, post-merger remnants with collapse times of $\sim 10\mathrm{ms}$ must be $\lesssim 10$Mpc to be measureable. This increases to $\sim 18-26$Mpc if we include the proposed Neutron star Extreme Matter Observatory (NEMO), increasing the effective volume by a factor of $\sim 30$.

9 pages, 3 figures